GENE INTERACTION AFFECTS THE ADDITIVE GENETIC VARIANCE IN SUBDIVIDED POPULATIONS WITH MIGRATION AND EXTINCTION

Area of Science:

• Population Genetics
• Evolutionary Biology
• Quantitative Genetics

Background:

• Understanding additive genetic variance is crucial for predicting evolutionary potential.
• Nonadditive genetic effects (dominance, epistasis) can influence the dynamics of additive variance.
• Subdivided populations present complex scenarios for genetic variation maintenance.

Purpose of the Study:

• To investigate how nonadditive genetic variance impacts additive genetic variance within local populations.
• To model the effects of migration, extinction, and recolonization on genetic variation in an infinite-island model.
• To determine the relationship between additive variance and population structure metrics like Fst.

Main Methods:

• Utilized a two-locus descent measure approach within an infinite-allele, infinite-island model.
• Developed matrix formulations for one- and two-locus descent measures to calculate equilibrium solutions.
• Derived an approximate relationship between additive variance within a deme and Fst.

Main Results:

• Additive genetic variance within a deme depends on species-level dominance and epistatic variation.
• Fst approximates the fraction of genic variance within a deme.
• Drift increases additive genetic variance, while migration decreases it at equilibrium in the presence of nonadditive effects.

Conclusions:

• Nonadditive genetic effects introduce complex dynamics to additive genetic variance in natural populations.
• Accurate assessment of evolutionary potential necessitates considering the spatial scale relative to natural selection.
• Ignoring nonadditive genetic variance can lead to misinterpretations of evolutionary capacity at both local and species levels.